Process and system for controlling engine speed

Abstract

A control process for controlling an engine speed governor of an engine is provided. The process comprises the steps of calculating the current engine power being developed by the engine, and determining an appropriate engine speed for the current engine power based upon a first engine map. The process then instructs the speed governor to adjust the engine speed in accordance with the first map if required. The process monitors for desired engine power requests, and calculates a power ratio of desired engine power versus current engine power upon receiving a desired engine power request. The process then establishes an engine speed adjustment value based upon a second engine map of power ratio versus speed adjustment value, and instructs the speed governor to adjust the engine speed in accordance with the speed adjustment value. A speed governor system incorporating the control process, and a work machine or vehicle incorporating such a system are also provided.

The invention claimed is: 
     
       1. A control process for controlling an engine speed governor of an engine, the process comprising the steps of:
 calculating the current engine power being developed by the engine; 
 determining an appropriate engine speed for the current engine power based upon a first engine map, the appropriate engine speed defined by the first engine map being a minimum speed for the current engine power; 
 instructing the speed governor to adjust the engine speed from a current engine speed to the appropriate engine speed in accordance with the first map if required; 
 monitoring for a request for additional power above the current engine power; 
 calculating a power ratio of total desired engine power to the current engine power if the request for additional power above the current engine power is received; 
 comparing the calculated power ratio to a second engine map correlating speed adjustment values to predetermined power ratios of total desired engine power to current engine power to determine a speed adjustment value correlated to the calculated power ratio, the speed adjustment value specifying a minimum engine speed to meet the request for additional power; and 
 instructing the speed governor to adjust the engine speed in accordance with the speed adjustment value. 
 
     
     
       2. The process of  claim 1 , wherein the speed governor is only instructed to adjust the engine speed in accordance with the first map if a difference between an actual engine speed and the appropriate engine speed is greater than 5% of the appropriate engine speed as determined by the first map. 
     
     
       3. The process of  claim 1 , wherein the engine drives a work machine or vehicle and the request for additional power is received from one or more ancillary components located on the work machine or vehicle, a manual operator input made by an operator of the vehicle, or both. 
     
     
       4. The process of  claim 3 , wherein the one or more ancillary systems are selected from the group comprising: a power take-off unit, a hydraulically-actuated component, or a global positioning satellite system. 
     
     
       5. A speed governor system for an engine, the system comprising:
 a plurality of engine sensors monitoring parameters associated with the engine; 
 a supervisory controller monitoring for a request for additional power above a current engine power being developed by the engine; 
 an engine controller which receives signals from the engine sensors, the supervisory controller, or both, and applies a control process in response to one or more of those signals, the control process comprising the steps of:
 calculating the current engine power being developed by the engine based upon one or more engine sensor signals; 
 determining an appropriate engine speed for the current engine power based upon a first engine map, the appropriate engine speed defined by the first engine map being a minimum speed for the current engine power; 
 generating a speed governor signal to adjust the engine speed from a current engine speed to the appropriate engine speed in accordance with the first map if required; 
 monitoring for the request for additional power from the supervisory controller; 
 calculating a power ratio of total desired engine power to the current engine power if the request for additional power from the supervisory controller is received; and 
 comparing the calculated power ratio to a second engine map correlating speed adjustment values to predetermined power ratios of total desired engine power to current engine power to determine a speed adjustment value correlated to the calculated power ratio, the speed adjustment value specifying a minimum engine speed to meet the request for additional power; 
 
 and the system further comprising: 
 an engine speed governor which adjusts the speed of the engine in response to the speed governor signal, the speed adjustment value established by the engine controller, or both. 
 
     
     
       6. The system of  claim 5 , further comprising at least one operator input sensor and at least one ancillary system sensor, wherein the supervisory controller receives the request for additional power from one or more of these operator input and ancillary system sensors. 
     
     
       7. A work machine or vehicle comprising a speed governor system for an engine in accordance with  claim 6 , further comprising at least one operator input device, wherein the at least one operator input sensor monitors the operator input device. 
     
     
       8. The work machine or vehicle of  claim 7 , further comprising at least one ancillary system selected from the group comprising: a power take-off unit, a hydraulically-actuated component, or a global positioning satellite system; and wherein the at least one ancillary system sensor monitors the at least one ancillary system. 
     
     
       9. A work machine or vehicle comprising a speed governor system for an engine in accordance with  claim 5 . 
     
     
       10. A control process for controlling an engine speed governor of an engine, the process comprising the steps of:
 calculating the current engine power being developed by the engine; 
 determining an appropriate engine speed for the current engine power based upon a first engine map, the appropriate engine speed defined by the first engine map being a minimum speed for the current engine power; 
 monitoring for a request for additional power above the current engine power; 
 in response to determining that no additional power is needed based on monitoring for the request for additional power:
 instructing the speed governor to adjust the engine speed from a current engine speed to the appropriate engine speed from the first map if the current engine speed is different than the appropriate engine speed; 
 
 in response to receiving the request for additional power:
 calculating a power ratio of total desired engine power to the current engine power, 
 comparing the calculated power ratio to a second engine map correlating speed adjustment values to predetermined power ratios of total desired engine power to current engine power to determine a speed adjustment value correlated to the calculated power ratio, the speed adjustment value specifying a minimum engine speed to meet the request for additional power, and 
 instructing the speed governor to adjust the engine speed in accordance with the speed adjustment value from the second engine map. 
 
 
     
     
       11. The process of  claim 10 , wherein the speed governor is only instructed to adjust the engine speed in accordance with the first map if the difference between the current engine speed and the appropriate engine speed is greater than 5% of the appropriate engine speed. 
     
     
       12. The process of  claim 10 , wherein the engine drives a work machine or vehicle and the request for additional power is received from one or more ancillary components located on the work machine or vehicle, a manual operator input made by an operator of the vehicle, or both. 
     
     
       13. The process of  claim 12 , wherein the one or more ancillary systems are selected from the group comprising: a power take-off unit, a hydraulically-actuated component, or a global positioning satellite system.